Chemotherapeutic efficacy is often hampered in neoplasias exhibiting multidrug-resistance (MDR), for which one major cause is the over-expression of ATP-binding cassette (ABC)-transporters like P-glycoprotein (P-gp, encoded by MDR1, ABCB1) or breast cancer resistance protein (BCRP, encoded by ABCG2) [11]. The gene discussed is PGP; the disease is neoplasm.